Rotary line-switch circuit



May '5, 1931.-.. H, ADAMS'" f 1,803,452

ROTARY LINE swrTcH CIRCUIT originalFiied Dec( e, 1926 giur-" PatentedMay 5, 1931 UNITED STATES PATENT ori-VICE HERBERT ADAMS, oryLiVE'nroo'L, ENGLAND, AssIGNon, BY MEsNE ASSIGNMENTS, `rro AssocIATnnTELEPHONE a TELEGRAPH COMPANY, or KANSAS CITY, Mrssocm i.

ROTARY LINE-SWITCH CIRCUIT 'Application :ned December e, 192e, serialNe.152,795, and in Greet Bil-itam January 7V, 192s.' Renewed May4,1929 Yi l 'l` hisinvention relates'to `telephonesystems and isparticularlyconcerned with animproved arrangement for reducing the un#guarded interval of a line or switch after it i ghasbeen taken into useandforensuring that line relay will be fully saturated when energizedover'high resistance junctionlines.

jWhererarelay; is energized over a high resistancefjunction line `viathe back contacts i v ofia relay energized in a local circuit as soon asan idle switch or line is seized,'it has been found necessaryv todelaythe operation of the relay energized in a local circuit to ensure full.saturation of the relayenergized over 151 thejun'ction circuit. Thiseffect has been obtained by placing a small copperl slug on the core ofthe relay in the local circuit,-but

while this arrangement ensures a satisfactorysaturation `of the relay inthe junction cir- Y l cuit, italso causes the local circuit relay to'beslowto `operate and slow-to release, thereby increasing the unguardedinterval of the line which ismarked engagedby the local cir'- cuit relaydue to its slownessto operate, while its increased slowness to releasemay cause other complications ducato. other relays restoring first;

According to oneffeature ofthe present inventionuthe-local circuit relayand4 junction 3o relay are arranged to jointly extend `guardingpotentialV tothe release,` conductor of 'a selectedline before the local.circuit relay fully operates to disconnect thefjunction rellay4vfromits energizing circuit. The local circuit relay isr'enderedquiclrto operate its `contactsiwhich disconnect the junctionrelay byproviding it :with anf'auXiliary winding `whichvis short-circuitedjointly by Vcontacts controlled by the junction relay and contactscontrolledby its own armature.

understoodand readily carried into effect, an

example of the invention will be fully described as applied to huntingswitches of aj, type`which 'select an vidle trunk responsive to acalling party-removing his receiver.

i The single figure of drawing shows by means of theusual `circuitdiagrams a pre-- ferred embodiment of my invention. 5G Theldrawingshowsalhunting'switch or rotary line switchv ofthe type which remains i onthe `contacts last used having a local circuit or switching relayprovided with an auxiliary `winding connected in a circult so vas torender the relay quick to operate cer-- tain contacts slow to operateother contacts and quick to release all its contacts.

Referring now tothe drawing, the slow release line relay L is energizedover line conductors 2, 3 via the back contacts of armaf` tures 8 and 9of switching relay Relay L upon energizing connects at armature 4, oneside of the driving-magnet DM and one side of the operating winding ofthe switching magnet DM will be operated by the earth potentialencountered upon the busy line.

Assuming that'thewipers are standing on an idle line, relay VK willimmediately ener gize ,in series with magnet DM and since its armaturesX and X are arranged. to operate before armatures 7 8 `and 9, armature XTwill complete the vshort-circuit for itsrauxiliary Windingand armatureX will connect guarding potential to `the test wiper P. Since theoperation of armature X 'renders the relay K slow in actuating armatures7, 8 and 9,V the energizingrcircuit of relay'L is j not brokenimmediately, and consequently In order'that the invention may ,be fullythis relaybecomes fully saturated before its circuit is opened and asthis relay is of the slow-to-release type, itwill maintain guardiingpotential on the release trunlrconductor trunk last used, meansincluding Aa disconnects relay L, and connects the line conductors 2 and3 through to the line wipers of the line switch, and the operation oit'armature 7 prepares a circuit for the meter M. The line switch remainsguarded and the relay'l energized by guarding potential fed back overwiper P and controlled by `a line relay energized over conductors 2 and3. Consequently the opening of the circuit 2, 3 by the calling partyhanging up his rec Aircr will cause guarding potential to -be removedfrom test wiper ly, whereupon relay 'I will immediately cleenergizesince the circuit of its auxiliary winding is now open at armature 6 bythe de-energization ot line relay L. iIn 1a modication the springs `X otthe switching relay K may be arranged as a -make-before-breakcombination vand shortcircuit the auxiliary winding upon initially q. l,1 energizing, and open the circuit upon iuny Having now described thenature 'ot Amy invention andthe manner in which itis to be used, what Iclaim as new is pointed out in the appended claims.

Vhat is claimed is:

l. In a telephone system, a switch including a line relay, aswitchingrrelay, means ttor operating said relays, and means renderedeffective after the switching relay has operated to a certaineXtent-todelay ythe tullopleration ofthe switching relay.

2. In a telephone system, a switch including a line relay,a switchingfrelaygmeans including a winding on the switching relay controlled byvcontacts on the line :relay ,and .short circuited after the switchingrelay has operated to a certain extent to delay vthe full operation otithe switching relay.

3. In a telephone system, a trunkselecting switch including `means forselecting-a trunk, aswitching relay arranged to'operateiunderpredetermined conditions, said switching irelay includinganoperating'winding land an additional winding, means forshortcircuiting said additional winding` when the switching relay `has:operated lto a certain extent =to reduccthe speed of further operationVoiivthe switching relay, and contacts-on the switching relay closedwhen the'switchin'g lrelay has operatedto its Jfull eXtent'to seize-theselected trunk.

4. In `a telephone system, -a trunkselecting switch having wipersnormally resting on the relay operated when the switch is taken `intouse to .move the wipers off of busy trunks only, means for releasing`the line relay -when the wipers rest on an idle trunk, said means beingdelayed in it-s action thereby insuring va complete energization of saidrelay prior to its release.

'5. In a telephone system, a trunk .select- :ing switch having wipersnormally .resting on the :trunk `last used, :means including a linerelay operated when the switch is taken into use to move the wipers ofi'of busy trunks, means for releasing the line relay when the wipers reston an idle trunk, and means controlled by the line relay for renderingsaid last named means slow `in its action, thereby insurinoF a completeenergization ot said relay prior to its release.

6. In a telephone system, a trunk selecting switch having wipersnormally resting on the 4.trunk last used, means including frontcontacts of a line relay operated when the switch =is taken into use `toindicate a -busy .condition of the switch and to move the wipers oli ofbusy trunks, means for releasing the line relay -when 'the wipers reston an idle 1trunk,:and means controlled by other 'l'rontcontacts `onth'eline're'lay'ifor delaying 'the action of said last name'dmeans'for a`predetermined period 'of time :thereby insuring acompleteen'ergizationSoitl said *line relay prior-to its release.

7. In a ltelephone system, a trunk f selecting ,switch normallyassociated withva trunk, a line relay operated `when the vswitch-.istaken.,

into :use to indicate rabusy :conditi-on of :the switch, means yfor`associating :said :switch 'with other trunks, |means for :releasing therelay `responsive .to the association :of the .switch with a .desiredtrunk,and means-cone,... r

trolled by the `line relay for 'delaying the operation o-.said lastnamed 'means 8. In aftelep'hone system, a trunkfselecting switch.including a :line irelay, 'means for operating fthe line relay when the.switch is :1 Vtaken into use, means for releasing ythe 2li-ne relayresponsive Eto the l:switch selecting a desired trunk, .and meanscontrolled lby the line relay for delaying :the op$eration 0;Said Vlastmeans.

`9. :In art-elephone system, atrunk'seleoting switch normally associatedwith la trunk, a iline :relay operated when fthe 'switch is `taken 'into'use to indicate a :bus-y condition lof the switch, mean-s `forassociating ysaid Vswitch with :other trunks, means for releasing "therelay when the switch is associated Vwith a desired trunk, means i for:delaying-:the release operati-on of the line 'relay for a 'periodioftime dependent upon 'its ldegree of l energization at theitime of.its-release, and meanscontrolled bythe line relay 'for insuring acompleteenergization ofsaid lline relay Aat the time of itsrelease.

l0. In a telephone system, a rtrurikselect- .ing switch having wipersnormally resting ergization of said line relay prior to its release,thereby fixing the time taken for the line relay to release regardlessof thebusy or idle condition of the trunk upon which the switch wipers`rest when the switch is seized. v

l1. In a trunk selecting switch of the type that when idle is inVcontactwith a trunk, a line relay operated responsive to the seizure ofthe switch, a. switching relay, means controlled by the switching relayfor opening the circuit of the line relay, and circuit connectionscontrolled by both relays for insuring the complete energization of theline relay at the time its circuit is opened. l

12. In a trunk selecting switch wherein a line relay operates responsiveto the seizure of the switch to institute the trunk hunting. movement ofthe switch and wherein a switching relay operates to open the circuit ofthe line relay and to stop movement of the switch and also prepare aholding circuit for itself, the initial operating circuit of theswitching relay including contacts of the line relay opened responsiveto the release thereof, characterized by the fact that there is providedmeans for insuring a saturation of the line relay at the time itscircuit is opened, thereby fixing the time taken for the line relay torelease regardless of whether the switch was or was not standing on anidle trunk when seized.

13. In a switch terminating a subscribers line adapted to select an idletrunk when used in an outgoing call and to disconnect the normal batteryand ground connections when seized in an incoming call, a switchingrelay the switching relay, and means including contacts of/both of saidrelays for short-circuiting said auxiliary winding to render theswitching relay slow to opera-te in outgoing calls.

18. In a rotary line switch, a line relay, a switching relay adapted tooperate with the line relay either operated or unoperated, an auxiliarywinding for the switching relay, and contacts on the line relay whenoperated for short-circuiting said auxiliary winding to render theswitching relay slow to operate.

19. In a rotary line switch, a fast acting cut-oil relay, meansoroperating said relay when the line is called, a line'relay forcontrolling the switch to select an idle trunk when the line is calling,means for operating said cut-off relay to complete connection to aselected trunk, and means controlled by said line relay for renderingsaid cut-ofi' relay slow to operate.

In witness whereof, I hereunto subscribe my name this 10th day ofNovember, A. D.

HERBERT ADAMS.

adapted to operate as a quick acting relay on v incoming calls, andmeans for rendering said relay slow to operate. on outgoing calls.

14. In a trunk selecting switch, a line relay, a switching relay, twowindings for said switching relay, means for operating the switchingrelay over one of lsaid windings, p

and means for rendering the switching relay slow to operate, said lastmeans including the other of said windings and contacts of both saidrelays. l Y

15. In a trunk selecting switch, a quick acting relay, a slowacting'relay, and means controlled jointly by said relays for renderingsaid first relayslow to operate under certain conditions. Y

16. In va trunk selecting switch including a line relay and a switchingrelay, an operating winding for the switching relay, an auxiliarywinding for the switching relay for rendering the relay slow-to operate,and

means for short circuiting said winding,

said means including contacts of the line relay and switching relay. A

17. In a rotary line switch, a line relay operated responsive to anoutgoing call, a

switching relay operated in both outgoing and incoming'calls, anauxiliary winding for

